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Ok, my answer, just from my experience and not a fact to be held as the truth in cour

Originally Posted by 98lee

So what is the acceptable amount of leakage on YOUR BIKE?

How does that compare with BMW's recommendation?

What would be the result of a failure on that particular system?

A leak is a warning. Will you heed it?

New brake seals in undamaged bores do not leak, even in cold weather. Worn or damaged seals or bores do.

No amount of leakage in a brake system is acceptable to me. I never had the luxury to see if that little "wetness' would stop. I was working on valued customers machines. I couldn't gamble.

BMW don't know SFS.

The results is the same as unforeseen rupture of a brake line, a skid mark in your underwear at the best.

A leak is a warning. It depends on how much patience you have and an understanding.

ALL NEW SEALS LEAK. There is another new topic and thread right there.

1997 R1100RT (Restored Basket Case) , 1981 KZ 440 LTD (Restored Basket Case)
3xR90/6, two just sold, one for a sidecar.
1983 K100RS for winter project, two K's sold and just acquired a very rough R80RT.

I am also familiar with powered hydraulic systems. (Military aircraft and industrial) The one thing that all your examples have in common and are not present in a brake system is a running PUMP.

Minor leakages (drops) will not effect the effectiveness of those systems as any oil leaks out that was supposed to lower the ramp or landing gear is replaced by the pump from the reservoir. The ramp or the landing gear will continue to lower until they reach their limit switches.

In a brake system, the "pump" is the master cylinder. Instead of running and providing what ever fluid is needed, it is limited by its single stroke displacement. If ANY brake fluid bypasses the seals, the resultant output is reduced. This causes the pads to have less travel/pressure available.

With a bike brake system, we are talking about less than 1/2 thimble full of fluid displacement. A few drops bypassing the seals is a huge percentage compared to the large systems you referred to. If your master runs out of travel before you stop, you may not like the outcome.

Dudes, slow down a little.
This aint jo mamma.
If the leak is acceptable to you there is nothing that anybody can say to make you think differently, but they might disagree, that is just the nature of the conversation.
My 2 cents, rear brake small leak Ok with me, front brake must be 100%

Wow! Lee has forgotten more about K75s than most will ever know, and generously (and patiently) shares his knowledge with any and all who ask. I'd suggest withholding opinion of him for some other forum, and instead if there is a disagreement challenge the content of his posts.

One can either take his voluminous knowledge or leave it, I would say however that in my many years of happily absorbing all of the many, many contributions he has made here, one ignores his advice at one's own peril. As a side note, some years ago I was stranded in the middle of West Virginia with a most vexing problem, I didn't know Lee and had never met him but he still offered and did call me and spent a good amount of time walking me through troubleshooting and fixing the problem.